The Certification of Vodka through the Use of Ion & Gas Chromatography
3058 Words
Boris Kevin Bayemi
Chemical Information Retrieval
Abstract
Governments and analytical chemists use ion and gas chromatography to determine the concentration of impurities (ethyl acetate, ethyl lactate, isobutanol, 1-propanol, 2-propanol, methanol, ethyl acetate and acetaldehyde) and ions (sodium, potassium, magnesium, calcium, chloride, and nitrate and sulfate) in vodka. The analysis and quantification of these impurities and ions are very helpful tools in the certification and regulation of vodka. The purpose of the certification and regulation of vodka is to protect both consumers and manufacturers of “true vodka” from false marketing schemes of cheaper brands (brand dilution) and acts of fraudulence.
Contents
Introduction
Gas Chromatography
Health Dangers of In Digesting Vodka Impurities
Ion Chromatography
Health Dangers of In Digesting Vodka Ionic Species
What is a Certified Vodka?
How Certification Works
Conclusion
Citations
Introduction
Vodka is a type of spirit that originated from Eastern Europe ("Gin & Vodka). Prior to 1940, Vodka was an unknown to Americans ("ProBrewer"). Today, vodka is a very common spirit. It can be taken as a shot or mix with juices, producing drinks like vodka martinis, vodka tonic, sex on the beach, etc ("Vodka"). The manufacturing of vodka is fairly easy.
The manufacturing begins with the mixing of either rye, wheat, corn, barley, potatoes, beets with sugar (or molasses) and yeast in water ("How To Make Vodka"). The starting materials are then heated to produce the “wort” ("ProBrewer") or "mash" ("How To Make Vodka"). Heat helps breaks down the starches, large carbohydrate groups, that turn into sugars via fermentation ("ProBrewer"). After fermentation, the wort is drained ("ProBrewer"). The liquid collected from draining the wort is called the "wash" ("ProBrewer"). After the fermentation process, the wash is put into the still ("How to Make Vodka") and is refluxed twice to produce an ethyl spirit ("ProBrewer"). After refluxing the wash, the solution is either filtered through charcoal or charbon ("ProBrewer"). The final process is the “cutting” of the spirit ("ProBrewer"), which means diluting the ethyl spirit with distilled water ("How To Make Vodka"). The majority of vodkas are “cut” to be 40% alcohol and 60% distilled water ("ProBrewer"). This process is what gives vodka it’s colorless, sharp taste. However, due to the simplicity of its production, vodka must be thoroughly regulated.
What often occurs is that wine, whiskey and industries use leftovers from their product to make vodka ("Stubb, 36"). According to US laws & regulations, classic vodka is to be near flavorless and neutral, and should be sold without distinctive character, aroma, taste or color ("Nasaw"). Vodka produced from leftovers of wine, whiskey and gin contain concentrations of flavorants, such as ethyl acetate, ethyl lactate and fusel oils (alcohols) ("Hori, 37S-41S). Fusel oils (alcohols) are a name used to refer to group of volatile compounds mainly composed of propanol, isobutanol, isoamyl alcohol and other constituents ("Hori, 37S-41S").
Fusel alcohols are derived from an amino acid catabolic pathway introduced by Felix Ehrlih ("Hazelwood, 2259-2266"). Amino acids contained in the vodka wort, are released from the starting materials during their mixing and heating ("Hazelwood, 2259-2266"). The amino acids, are used by the Ehrlich pathway during fermentation ("Hazelwood, 2259-2266"). These amino acids are converted into an α-keto acids. The yeast then converts them into fusel alcohols or acids via the Ehrlich pathway ("Hazelwood, 2259-2266"). These fatty acids (fusel acids), esters and alcohols (contained in fusel oils) are normally present at low concentration levels in vodka ("Yashin, 1121-1127"). However, even at such low levels, these left over derived vodkas do not qualify as classic vodkas.
Compound 1: an example of an alpha keto acid ("EMBL-EBI")
Advertising these vodkas as "classic" or "true" vodkas is misleading to consumers and detrimental to the vodka industry because only vodka connoisseurs can truly taste the difference between premium vodkas and cheap or “leftover” based ones (Nasaw). As such, regular consumers are victims of misleading marketing schemes. Fraud scenarios are very common in the case of premium or brand spirits, since there is a strong economic incentive to do so ("Lachemeier, 283-289"). A bar can easily sell to customers a cheaper brand whilst claiming it’s a more expensive one and make a good profit off the act of fraud. In worst cases, cheap or “leftover” based vodkas can contain illegal additives and concentrations of chemical compounds in vodka, such as methanol or ethylene glycol, which can lead to harmful health side effects or death ("Lachemeier, 283-289"). Regulators must rely on analytical chemists to determine the quality of vodkas before allowing them to be introduced in the market.
The main goal of analytical chemist is to deduce whether the analytical samples of vodka x or y meets the standards. In other words, if the concentrations of acetaldehydes, esters, methanol and fusel oils are found to be higher than corresponding values and strengths than specified value by alcohol authority, then given sample fails to comply with the quality standard ("Reshetnikova, 1013-1016"). A common type of analytical technique used to determine the chemical makeup of vodka, and whether the spirit complies with the quality standard, is chromatography. Chromatography is the most versatile technique for the analysis of foods and beverages because it is a sensitive and rapid technique (Yashin, "1121-1127") that is selective enough to detect volatile fatty acids and nonvolatile poly functional acids ("Ng, 309-318") that may exist in spirits. Within the field of chromatography, there are two techniques used by analytical chemist to co-analyze spirits, gas and ion chromatography (ion-exchange chromatography).
Gas Chromatography
Gas chromatography (GC) is a technique for separating the chemical component of mixtures that relies on the difference in partitioning speeds between a flowing mobile phase and a stationary phase ("Reshetnikova, 1013-1016"). The sample is carried by a moving stream of gas that passes through a tube packed with finely divided solid or coated film of a liquid ("Reshetnikova, 1013-1016"). There are numerous GC techniques and which technique is most suitable depends on the experimenter. A very popular technique used for quality control of vodka is SPME-GC-MS (Solid Phase Micro Extraction-Gas Chromatography-Mass Spectroscopy).
SPME-GC-MS offers the high degree of sensitivity needed to trace target analysis by small volume direct injection. In general, the technique usually begins with the introduction a sample along with a carrier gas such as Hydrogen, Helium, Argon, Nitrogen, Methane/Argon mixture or synthetic air ("The Linde Group"). The choice of carrier gas depends entirely on type of detector used, the constituents to be analyzed, and amount of time the experimenter has ("The Linde Group"). If the experimenter does not have the luxury of time, hydrogen, which has the lowest viscosity and highest mobile phase velocity amongst the gases mentioned above, would be best suited since it has the shortest analysis time ("The Linde Group, 1-5"). If quality is of up most importance, than Helium is better, since Helium tends to give the best overall performance and peak resolutions for numerous of applications ("The Linde Group, 1-5"). Most GC-MS tend to use Helium as carrier gas. The purity of carrier gas is also very important; impurities in the carrier may reduce the performance, maintenance, lifetime of the column(s), thus reducing the sensitivity and accuracy of GC ("The Linde Group, 1-5"). The purity of the sample is a critical factor for the very same reasons.
Alcoholic beverage samples must be prepared before being injected due to high levels of contamination of the liner by nonvolatile compounds ("Ng, 309-318"). The sample is preferably prepared by extraction. SPME, an extraction technique developed by Berlardi & Pawliszyn based on the establishment of analyte equilibrium between the sample and polymeric coating on fused silica fiber ("Ghaffer, 1255-1262"), is very popular extraction method used to prepare alcoholic beverage samples due to its high concentration power, simplicity, cost effectiveness ("Ng, 309-318") and compatibility with numerous compounds ("Ghaffer, 1255-1262"). Alcohol beverage samples are vaporized before being injected into the carrier stream. The gas stream is passed through the packed column(s), through which the constituents of the sample travel at different speeds ("The Linde Group"). Their speeds are influenced by the degree with which they interact with the stationary nonvolatile phase ("The Linde Group"). Constituents that have a greater degree of interaction with the stationary nonvolatile phase move at a slower pace than those with smaller degrees of interaction. As the constituents leave the column(s), their quantity is quantified by a detector in absorbance ("The Linde Group"). In the case of alcoholic beverages, the constituents are collected and analyzed further by mass spectrometry ("The Linde Group"). Gas chromatography is very good at analyzing and quantifying amounts of 1-propanol, 2-propanol, methanol, ethyl acetate and acetaldehyde (refer to figure 3 for visual image of chemical compounds) in vodka and other spirits, chemicals that may still persist even after purifying vodka from the fusel oils. This is very important since these chemicals can cause serious health issues and do not qualify as “pure vodkas” when present in certain concentrations; knowing their acceptable amounts is a must.
Figure 2: Schematic of a GC-MS ("Thet")
Health Dangers of In Digesting Vodka Impurities
2-Propanol ("Right to Know: Hazardous Substance Fact Sheet.") and Ethyl Acetate ("National Pollutant Inventory") can both irritate the throat, effect liver and kidney function, and in more serious cases, lead to loss of coordination, unconsciousness and death. 1-Propanol can cause gastrointestinal irritation, nausea, vomiting and diarrhea ("Fischer Scientific"). Acetaldehyde, like the previously mentioned chemicals, has shown to be associated to liver damage ("Inchem"). Finally, Methanol can lead to vision problems (which include blindness) and death if ingested ("Butler"). Methanol may be the most poisonous amongst the fusel oils since even a small concentration can reduce vision. Most of these chemical compounds share similar side effects. The ingestion of all of these chemicals at once is akin to taking a shot of a concoction of poison. As such, the importance of detect and quantify their concentrations in vodka is critical due to health implication associated with the respective chemicals. Like gas chromatography, ion chromatography is also used to detect the unwanted species in vodka, especially the anion-cation concentrations in vodka.
Ion Chromatography
The ionic composition of vodka depends on water and various additives used in its production ("Arbuzov, 515-521"). Ion chromatography (IC) allows the separation of ions and polar molecules based on their charge. IC is very similar to HPLC (High Performance Low Chromatography) ("Frtiz 2000"). Like HPLC, IC uses a buffered aqueous solution as carrier ("Fritz 2000"). Like most carriers used in chromatography, the aqueous solution carries the sample and its constituents through the column(s) to the detector (. IC’s has a mobile and stationary phase ("Fritz 2000"). The mobile phase, describe earlier, transports the sample to the stationary phase. The stationary phase usually contains a resin or gel matrix of agarose or cellulose beads with covalently bonded charged functional groups ("Fritz 2000"). The sample and its constituents are trapped in the resin or gel, but can move or travel through it thanks buffered solution. The speeds at which the constituents move depend on how attracted they are to the buffered solution (Gjerde, 49-61"). For example, a negatively charged constituent can be easily displaced by buffered solution containing large concentrations of positively charged ion whereas a constituent with a temporary dipole will displace at a slower pace ("Gjerde, 49-61"). The only difference between HPLC and IC is the detector(s) ("LC GC North America").
The detectors for IC can either be a conductometric and amperometric detector or both, along with a regular absorbance detector ("Arbuzov, 515-521"). Both detectors are electrochemical methods. The difference lies in their sensitivity; conductometric detectors are more universally used as most ions and polar molecules are charged strongly enough to be detected by the detector, however some molecules do not dissociate easily into polar molecules or ions (usually molecules with a pH above 7) ("Weiss 2008")). Such molecules are not or cannot be detected by conductivity but are detectable by amperometric detection ("Weiss 2008"). Since alcoholic beverages contain a wealth of inorganic and organic compound, it is in the experimenter’s benefit to use both an amperometric and conductometric detector. Amperometric detectors can detect sulfites and sugars better in alcohol whereas conductometric detector anions better ("Arbuzov, 515-521"). Common cations and anions detected by ion chromatography in vodka are sodium, potassium, magnesium, calcium, chloride, and nitrate and sulfate ("Arbuzov, 515-521"). Similar to the impurities contained in fusel oils (alcohols), these ions can prove to be poisonous to our body and cannot be marketed as pure vodkas if present in unacceptable concentrations.
Figure 8: Schematic drawing of an IC ("Mishra")
Health Dangers of In Digesting Vodka Ionic Species
Although most of these ions are vital to our bodies, large of concentrations of them residing in the body due to kidney damage or failure, which can be induce by alcohol, can harm bodily functions. As such, it is important to know the acceptable amount of these ions to avoid allowing harmful vodkas reaching the market. Sodium can increase the risk of high blood pressure, which is major risk factor in stroke, heart and kidney disease when found in excessive concentrations ("Health Canada"). High potassium levels also increases heart risk, such as irregular heartbeats ("Lenntech"). In addition, similar to sulfate ("US EPA"), potassium can irritate the stomach which may lead to stomach cramping, diarrhea and disruption of the digestion process ("Lenntech"). Excessive magnesium can induce changes in mental status, nausea, diarrhea, appetite loss, muscles weakness, difficulty breathing, extremely low blood pressure and irregular heartbeat ("NIH"). Health risk associated with excessive calcium is hypercalcemia, which can cause renal insufficiency, tissue calcification, hypercalciuria, kidney stones and constipation ("NIH"). The dangers with nitrate has do with the fact that it can be converted into a nitrosamine (suspected carcinogen), and nitrite ( which changes hemoglobin into methemoglobin, thus resulting in methmoglobinemia). As one may have noticed, the harmful side effects of these ions and fusil oils contained in vodka are very similar and compliment themselves. As pointed earlier, regulation is a must and information obtained from ion and gas chromatography is very important. However, despite having similarities, no vodka is the same. The concentration of these constituents not only differs from manufacturer to manufacture, but they are also different from bottle to bottle from the same manufacturer.
What is a Certified Vodka?
Deeming whether a vodka brand or bottle is safe or “pure vodka” is very tricky for analytical chemist since they have to make numerous comparisons. The bottle’s anion-cation and fusel oil composition is usually compared between manufacturers of the same kind of vodka, between bottles from different years from the same manufacturer, and between the bottle in questions and denatured/adulterated bottles. In addition, the country of origin is of great concern. For example, spirits bottled in Russia and in Germany display large differences ("Lachenmeier, 105-110")). The concentration of anions in Russia vodkas tend to be lower than German ones, 0.2 – 7.2 mg/l compared to 11.5-147.6 mg/l ("Lachenmeier, 105-110"). Despite all of this variance, analytical chemist rely on the fact that premium vodkas, such as Smirnoff Vodka, tend to have very low anion and fusel oils concentrations due to the use of premium ingredients and manufacturing techniques such as ion exchange or reverse osmosis for deionization ("Lachenmeier, 105-110"). Whereas manufacturers of cheaper brands tend to bottle their vodkas with standard tap water without further water treatment and cheaply distilled ethyl spirit, therefore their vodkas tend to have higher ionic and fusel oil concentrations ("Lachenmeier, 105-110"). The methodology of comparing of a bottle’s anion-cation and fusel oil composition between manufacturers of the same kind of vodka, between bottles from different years from the same manufacturer, and between the bottle in questions and denatured/adulterated bottles as a mean of certification of the bottle has been conducted by several analytical chemist in their experiments; experiments such as “The Use of Ion Chromatography to Detect Adulteration of Vodka and Rum” by the Drik W. Lachenmeier group, and “Identification of Vodkas by Ion Chromatography and Gas Chromatography” by V.N. Arbuzov and S.A. Savchuck, have successfully identified the difference between pure vodkas and adulterated/denatured by means of comparisons.
How Certification Works
In “The Use of Ion Chromatography to Detect Adulteration of Vodka and Rum” by the Drik W. Lachenmeier group, they determined that the suspicious vodka samples were in fact suspicious by comparing the quantity of acetaldehyde and isoamyl alcohol (determined by GC), and chloride, nitrate and sulphate (anions determined by IC) between authentic Smirnoff, authentic German Vodka and the suspected Smirnoff vodka samples. The suspected Smirnoff vodka samples were found to truly be German Vodka. According to the study, the authentic Smirnoff and German Vodka sample had similar concentrations acetaldehyde, isoamyl alcohol and percentage per volume of ethanol, but concentrations of chloride, nitrate and sulphate that were not detected in the authentic Smirnoff were present in the authentic German vodka samples. The nitrate concentrations were found to range from 14.5 to 12.8 mg/l in the three vodka samples and 15.5 mg/l in the German vodka sample. The chloride concentrations were found to range from 8 to 9.3 mg/l and 9.3 mg/l in the German vodka sample. The sulfate concentration was found to range from 15.5 mg/l to 21.2 mg/l and 17.1 mg/l in the German vodka sample (refer to figure 3). The data collected clearly proved that the bar was guilty of an act of fraudulence. In addition, the group analyzed different brands of vodkas to have a quantified idea of the composition of a good sample (refer to figure 2). V.N. Arbuzov and S.A. Savchuck conducted their experiment in a similar manner (their investigation occurred before that of Drik W. Lachenmeier group).
Figure 9: Comparison of different brands vodka by Lachenmeier group ("Lachenmeier, 105-110")
Figure 10: Comparison of suspected vodka samples by Lachenmeier group ("Lachenmeier, 105-110")
In V.N. Arbuzov’s and S.A. Savchuck’s paper, “Identification of Vodkas by Ion Chromatography and Gas Chromatography”, the authors argued that the co-analysis of vodka by IC and GC-MS is better than solemnly analyzing vodka by GC-MS. Like Drik W. Lachenmeier’s group, V.N. Arbuzov and S.A. Savchuck based their conclusion on the comparison of concentration of anion-cation and impurities in vodka between the sample and control (refer to figures 4, 5 and 6). For example, when comparing the concentration of acetaldehyde, ethyl acetate, methanol, 1-propanol and 2-propanol between Charka vodka and it’s adulterated form, the concentration of acetaldehyde, ethyl acetate and 2-propaol were higher in the adulterated form and the concentration of methanol were lower in adulterated vodka. They also found differences in the ionic composition of the Charka vodka and its adulterated form where sodium, sulfate, potassium and chloride were higher in concentration in Charka vodka than in its adulterated form, and nitrate, calcium and magnesium were lower in concentration in Charka vodka than in its adulterated form. This data provided them with a benchmark, a quantified definition of what proper Charka vodka was composed of. With this data, they could have easily determined whether a manufacturer or bar owner was guilty of fraud. In addition, the two scientist collected data on the concentrations of ions and impurities for bottles of different trades and bottles form different years from the same trade. Similar to Drik W. Lachenmeier’s group, that data was used to prove how ion chromatography can effectively be used to detect trends in the ion concentrations of bottles from the same trade, thus providing the experimenters with more information as whether a bottle should be certified. Their papers are perfect examples of how chemists use GC and IC techniques to regulate vodka manufacturing.
Figure 11: Anion-cation analysis by V.N Arbuzov & S.A Savchuck between manufacturer and amongst a manufacturer with their adulterated forms ("Arbuzov, 515-521")
Figure 12: Impurities analysis by V.N Arbuzov & S.A Savchuck between manufacturers & their adulterated forms ("Arbusov, 515-521")
Figure 13: Impurities analysis by V.N Arbuzov & S.A Savchuck amongst a manufacture and adulterated form ("Arbuzov, 515-521")
Conclusion
As V.N. Arbuzov and S.A. Savchuck pointed out, the use of ion and gas chromatography is the most effective means of identifying, certifying and regulating vodka as it characterizes two major constituents of vodka, water and alcohol. As the demonstrated in the collected data by V.N. Arbuzov and S.A. Savchuck and the Drik W. Lachenmeier’s group, the difference in the composition vodkas, are quite similar. That is why chemist must rely on highly sensitive techniques such as GC and IC, to protect the public from potential harms and acts of fraudulence. GC provides them with information on the amount of impurities such as 1-propanol, 2-propanol, methanol, ethyl acetate and acetaldehyde while IC is better at collecting data on amounts of ions such as sodium, potassium, magnesium, calcium, chloride, and nitrate and sulfate. Although these constituents are found in small concentrations in most vodkas, even adulterated ones, they can prove to still be harmful to pregnant women and those with poor liver or kidney function. It is for the very same reasons that it is medically ill advised to heavily drink on a regular basis. Alcohol is poisonous to our bodies and techniques like GC and IC help governments protect society from intoxicating itself to death.
Web ) Stubb, Alexander. "European Voices." Blue Wings. 2006: 36. . 20 Nov. 2012.
Nasaw, Daniel. "Why are there so many brands of vodka on sale?." BBC. 7 2012. Web ) . 20 Nov 2012.
Hori, Hisako. "Effects of Fusel Oil on Animal Hangover Models." Alcoholism: Clinical and Experimental Research. 27. (2003): 37S - 41S. DOI. 28 Nov. 2012.
Hazelwood, Lucie. "The Ehrlich Pathway for Fusel Alcohol Production."Applied and Environmental Biology. 74.8 (2008): 2259-2266. DOI . 4 Dec. 2012.
Yashin, Ya. "Analysis of Food Products and Beverages Using High Performance Liquid Chromatography and Ion Chromatography with Electrochemical Detectors." Journal of Analytical Chemistry. 59.12 (2004): 1121-1127. DOI . 20 Nov. 2012.
EMBL-EBI X Numbers in MACiE . N.d. EMBL-EBI. Web . 8 Dec 2012
Lachemeier, Dirk. "Rapid and Mobile Brand Authentication of Vodka Using Conductivity Measurement." Microchimica Acta. 160.1-2 (2008): 283-289. DOI. 5 Dec. 2012.
Reshetnikova, V.N. "Identification of Raw Materials for the Production of Vodkas Based on the Results of Gas-Liquid Chromatographic Analysis with the Use of Fuzzy Logic."Journal of Analytical Chemistry. 62.11 (2007): 1013-1016. DOI. 20 Nov. 2012.
Ng, Lay-Keow. "Analysis by Gas Chromatography/Mass Spectroscopy of Fatty Acids and Esters in Alcoholic Beverages and Tobaccos." Analytica Chimica. 465. (2002): 309-318. DOI. 20 Nov. 2012.
."Gas Chromatography." The Linde Group. Linde AG. Web. 20 Nov 2012.
."GC-MS: THE SUPERIOR FORENSIC TOOL." Linde Gas. The Linde Group, 22 2011. Web. 28 Nov 2012
Ghaffer, Sajeela. "Determination of VOC in potable Water Using Solid Phase Micro Extraction-Gas Chromatography." Arab Journal Science Engineering. 37. (2012): 1255–1262. DOI. 28 Nov. 2012.
Thet, Kyaw. Gas Chromatography. N.d. UCDavis ChemWiki, Davis. Web. 6 Dec 2012
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"Environmental Health Criteria 167: Acetaldehyde." . Inchem. Web. 30 Nov 2012.
Butler, Ben. "Methanol Exposure and Health Risks."Envirosafe. N.p., 4 2011. Web. 30 Nov. 2012.
Arbuzov, V.N. "Identification of Vodkas by Ion Chromatography and Gas Chromatography." Journal of Anaytical Chemistry. 57.5 (2002): 515-521. DOI. 30 Nov. 2012.
Fritz, James. Ion chromatography. 4th. Weinheim, New York: Wiley-VCH, 2000. eBook.
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3058 Words
Boris Kevin Bayemi
Chemical Information Retrieval
Abstract
Governments and analytical chemists use ion and gas chromatography to determine the concentration of impurities (ethyl acetate, ethyl lactate, isobutanol, 1-propanol, 2-propanol, methanol, ethyl acetate and acetaldehyde) and ions (sodium, potassium, magnesium, calcium, chloride, and nitrate and sulfate) in vodka. The analysis and quantification of these impurities and ions are very helpful tools in the certification and regulation of vodka. The purpose of the certification and regulation of vodka is to protect both consumers and manufacturers of “true vodka” from false marketing schemes of cheaper brands (brand dilution) and acts of fraudulence.
Contents
Introduction
Gas Chromatography
Health Dangers of In Digesting Vodka Impurities
Ion Chromatography
Health Dangers of In Digesting Vodka Ionic Species
What is a Certified Vodka?
How Certification Works
Conclusion
Citations
Introduction
Vodka is a type of spirit that originated from Eastern Europe ("Gin & Vodka). Prior to 1940, Vodka was an unknown to Americans ("ProBrewer"). Today, vodka is a very common spirit. It can be taken as a shot or mix with juices, producing drinks like vodka martinis, vodka tonic, sex on the beach, etc ("Vodka"). The manufacturing of vodka is fairly easy.
The manufacturing begins with the mixing of either rye, wheat, corn, barley, potatoes, beets with sugar (or molasses) and yeast in water ("How To Make Vodka"). The starting materials are then heated to produce the “wort” ("ProBrewer") or "mash" ("How To Make Vodka"). Heat helps breaks down the starches, large carbohydrate groups, that turn into sugars via fermentation ("ProBrewer"). After fermentation, the wort is drained ("ProBrewer"). The liquid collected from draining the wort is called the "wash" ("ProBrewer"). After the fermentation process, the wash is put into the still ("How to Make Vodka") and is refluxed twice to produce an ethyl spirit ("ProBrewer"). After refluxing the wash, the solution is either filtered through charcoal or charbon ("ProBrewer"). The final process is the “cutting” of the spirit ("ProBrewer"), which means diluting the ethyl spirit with distilled water ("How To Make Vodka"). The majority of vodkas are “cut” to be 40% alcohol and 60% distilled water ("ProBrewer"). This process is what gives vodka it’s colorless, sharp taste. However, due to the simplicity of its production, vodka must be thoroughly regulated.
What often occurs is that wine, whiskey and industries use leftovers from their product to make vodka ("Stubb, 36"). According to US laws & regulations, classic vodka is to be near flavorless and neutral, and should be sold without distinctive character, aroma, taste or color ("Nasaw"). Vodka produced from leftovers of wine, whiskey and gin contain concentrations of flavorants, such as ethyl acetate, ethyl lactate and fusel oils (alcohols) ("Hori, 37S-41S). Fusel oils (alcohols) are a name used to refer to group of volatile compounds mainly composed of propanol, isobutanol, isoamyl alcohol and other constituents ("Hori, 37S-41S").
Fusel alcohols are derived from an amino acid catabolic pathway introduced by Felix Ehrlih ("Hazelwood, 2259-2266"). Amino acids contained in the vodka wort, are released from the starting materials during their mixing and heating ("Hazelwood, 2259-2266"). The amino acids, are used by the Ehrlich pathway during fermentation ("Hazelwood, 2259-2266"). These amino acids are converted into an α-keto acids. The yeast then converts them into fusel alcohols or acids via the Ehrlich pathway ("Hazelwood, 2259-2266"). These fatty acids (fusel acids), esters and alcohols (contained in fusel oils) are normally present at low concentration levels in vodka ("Yashin, 1121-1127"). However, even at such low levels, these left over derived vodkas do not qualify as classic vodkas.
Figure 1: Ehrlich Pathway ("Hazelwood, 2259-2266")
Compound 1: an example of an alpha keto acid ("EMBL-EBI")
Advertising these vodkas as "classic" or "true" vodkas is misleading to consumers and detrimental to the vodka industry because only vodka connoisseurs can truly taste the difference between premium vodkas and cheap or “leftover” based ones (Nasaw). As such, regular consumers are victims of misleading marketing schemes. Fraud scenarios are very common in the case of premium or brand spirits, since there is a strong economic incentive to do so ("Lachemeier, 283-289"). A bar can easily sell to customers a cheaper brand whilst claiming it’s a more expensive one and make a good profit off the act of fraud. In worst cases, cheap or “leftover” based vodkas can contain illegal additives and concentrations of chemical compounds in vodka, such as methanol or ethylene glycol, which can lead to harmful health side effects or death ("Lachemeier, 283-289"). Regulators must rely on analytical chemists to determine the quality of vodkas before allowing them to be introduced in the market.
The main goal of analytical chemist is to deduce whether the analytical samples of vodka x or y meets the standards. In other words, if the concentrations of acetaldehydes, esters, methanol and fusel oils are found to be higher than corresponding values and strengths than specified value by alcohol authority, then given sample fails to comply with the quality standard ("Reshetnikova, 1013-1016"). A common type of analytical technique used to determine the chemical makeup of vodka, and whether the spirit complies with the quality standard, is chromatography. Chromatography is the most versatile technique for the analysis of foods and beverages because it is a sensitive and rapid technique (Yashin, "1121-1127") that is selective enough to detect volatile fatty acids and nonvolatile poly functional acids ("Ng, 309-318") that may exist in spirits. Within the field of chromatography, there are two techniques used by analytical chemist to co-analyze spirits, gas and ion chromatography (ion-exchange chromatography).
Gas Chromatography
Gas chromatography (GC) is a technique for separating the chemical component of mixtures that relies on the difference in partitioning speeds between a flowing mobile phase and a stationary phase ("Reshetnikova, 1013-1016"). The sample is carried by a moving stream of gas that passes through a tube packed with finely divided solid or coated film of a liquid ("Reshetnikova, 1013-1016"). There are numerous GC techniques and which technique is most suitable depends on the experimenter. A very popular technique used for quality control of vodka is SPME-GC-MS (Solid Phase Micro Extraction-Gas Chromatography-Mass Spectroscopy).
SPME-GC-MS offers the high degree of sensitivity needed to trace target analysis by small volume direct injection. In general, the technique usually begins with the introduction a sample along with a carrier gas such as Hydrogen, Helium, Argon, Nitrogen, Methane/Argon mixture or synthetic air ("The Linde Group"). The choice of carrier gas depends entirely on type of detector used, the constituents to be analyzed, and amount of time the experimenter has ("The Linde Group"). If the experimenter does not have the luxury of time, hydrogen, which has the lowest viscosity and highest mobile phase velocity amongst the gases mentioned above, would be best suited since it has the shortest analysis time ("The Linde Group, 1-5"). If quality is of up most importance, than Helium is better, since Helium tends to give the best overall performance and peak resolutions for numerous of applications ("The Linde Group, 1-5"). Most GC-MS tend to use Helium as carrier gas. The purity of carrier gas is also very important; impurities in the carrier may reduce the performance, maintenance, lifetime of the column(s), thus reducing the sensitivity and accuracy of GC ("The Linde Group, 1-5"). The purity of the sample is a critical factor for the very same reasons.
Alcoholic beverage samples must be prepared before being injected due to high levels of contamination of the liner by nonvolatile compounds ("Ng, 309-318"). The sample is preferably prepared by extraction. SPME, an extraction technique developed by Berlardi & Pawliszyn based on the establishment of analyte equilibrium between the sample and polymeric coating on fused silica fiber ("Ghaffer, 1255-1262"), is very popular extraction method used to prepare alcoholic beverage samples due to its high concentration power, simplicity, cost effectiveness ("Ng, 309-318") and compatibility with numerous compounds ("Ghaffer, 1255-1262"). Alcohol beverage samples are vaporized before being injected into the carrier stream. The gas stream is passed through the packed column(s), through which the constituents of the sample travel at different speeds ("The Linde Group"). Their speeds are influenced by the degree with which they interact with the stationary nonvolatile phase ("The Linde Group"). Constituents that have a greater degree of interaction with the stationary nonvolatile phase move at a slower pace than those with smaller degrees of interaction. As the constituents leave the column(s), their quantity is quantified by a detector in absorbance ("The Linde Group"). In the case of alcoholic beverages, the constituents are collected and analyzed further by mass spectrometry ("The Linde Group"). Gas chromatography is very good at analyzing and quantifying amounts of 1-propanol, 2-propanol, methanol, ethyl acetate and acetaldehyde (refer to figure 3 for visual image of chemical compounds) in vodka and other spirits, chemicals that may still persist even after purifying vodka from the fusel oils. This is very important since these chemicals can cause serious health issues and do not qualify as “pure vodkas” when present in certain concentrations; knowing their acceptable amounts is a must.
Figure 2: Schematic of a GC-MS ("Thet")
Health Dangers of In Digesting Vodka Impurities
2-Propanol ("Right to Know: Hazardous Substance Fact Sheet.") and Ethyl Acetate ("National Pollutant Inventory") can both irritate the throat, effect liver and kidney function, and in more serious cases, lead to loss of coordination, unconsciousness and death. 1-Propanol can cause gastrointestinal irritation, nausea, vomiting and diarrhea ("Fischer Scientific"). Acetaldehyde, like the previously mentioned chemicals, has shown to be associated to liver damage ("Inchem"). Finally, Methanol can lead to vision problems (which include blindness) and death if ingested ("Butler"). Methanol may be the most poisonous amongst the fusel oils since even a small concentration can reduce vision. Most of these chemical compounds share similar side effects. The ingestion of all of these chemicals at once is akin to taking a shot of a concoction of poison. As such, the importance of detect and quantify their concentrations in vodka is critical due to health implication associated with the respective chemicals. Like gas chromatography, ion chromatography is also used to detect the unwanted species in vodka, especially the anion-cation concentrations in vodka.
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Figure 3: 1) Acetaldehyde ("ethanal")*, 2) Ethyl Acetate ("ethyl acetate")*, 3) 1-Propanol ("propan-1-ol")*, 4) 2-Propanol ("isopropanol)*, 5) Methanol ("methanol")*; * = citations
Ion Chromatography
The ionic composition of vodka depends on water and various additives used in its production ("Arbuzov, 515-521"). Ion chromatography (IC) allows the separation of ions and polar molecules based on their charge. IC is very similar to HPLC (High Performance Low Chromatography) ("Frtiz 2000"). Like HPLC, IC uses a buffered aqueous solution as carrier ("Fritz 2000"). Like most carriers used in chromatography, the aqueous solution carries the sample and its constituents through the column(s) to the detector (. IC’s has a mobile and stationary phase ("Fritz 2000"). The mobile phase, describe earlier, transports the sample to the stationary phase. The stationary phase usually contains a resin or gel matrix of agarose or cellulose beads with covalently bonded charged functional groups ("Fritz 2000"). The sample and its constituents are trapped in the resin or gel, but can move or travel through it thanks buffered solution. The speeds at which the constituents move depend on how attracted they are to the buffered solution (Gjerde, 49-61"). For example, a negatively charged constituent can be easily displaced by buffered solution containing large concentrations of positively charged ion whereas a constituent with a temporary dipole will displace at a slower pace ("Gjerde, 49-61"). The only difference between HPLC and IC is the detector(s) ("LC GC North America").
The detectors for IC can either be a conductometric and amperometric detector or both, along with a regular absorbance detector ("Arbuzov, 515-521"). Both detectors are electrochemical methods. The difference lies in their sensitivity; conductometric detectors are more universally used as most ions and polar molecules are charged strongly enough to be detected by the detector, however some molecules do not dissociate easily into polar molecules or ions (usually molecules with a pH above 7) ("Weiss 2008")). Such molecules are not or cannot be detected by conductivity but are detectable by amperometric detection ("Weiss 2008"). Since alcoholic beverages contain a wealth of inorganic and organic compound, it is in the experimenter’s benefit to use both an amperometric and conductometric detector. Amperometric detectors can detect sulfites and sugars better in alcohol whereas conductometric detector anions better ("Arbuzov, 515-521"). Common cations and anions detected by ion chromatography in vodka are sodium, potassium, magnesium, calcium, chloride, and nitrate and sulfate ("Arbuzov, 515-521"). Similar to the impurities contained in fusel oils (alcohols), these ions can prove to be poisonous to our body and cannot be marketed as pure vodkas if present in unacceptable concentrations.
Figure 8: Schematic drawing of an IC ("Mishra")
Health Dangers of In Digesting Vodka Ionic Species
Although most of these ions are vital to our bodies, large of concentrations of them residing in the body due to kidney damage or failure, which can be induce by alcohol, can harm bodily functions. As such, it is important to know the acceptable amount of these ions to avoid allowing harmful vodkas reaching the market. Sodium can increase the risk of high blood pressure, which is major risk factor in stroke, heart and kidney disease when found in excessive concentrations ("Health Canada"). High potassium levels also increases heart risk, such as irregular heartbeats ("Lenntech"). In addition, similar to sulfate ("US EPA"), potassium can irritate the stomach which may lead to stomach cramping, diarrhea and disruption of the digestion process ("Lenntech"). Excessive magnesium can induce changes in mental status, nausea, diarrhea, appetite loss, muscles weakness, difficulty breathing, extremely low blood pressure and irregular heartbeat ("NIH"). Health risk associated with excessive calcium is hypercalcemia, which can cause renal insufficiency, tissue calcification, hypercalciuria, kidney stones and constipation ("NIH"). The dangers with nitrate has do with the fact that it can be converted into a nitrosamine (suspected carcinogen), and nitrite ( which changes hemoglobin into methemoglobin, thus resulting in methmoglobinemia). As one may have noticed, the harmful side effects of these ions and fusil oils contained in vodka are very similar and compliment themselves. As pointed earlier, regulation is a must and information obtained from ion and gas chromatography is very important. However, despite having similarities, no vodka is the same. The concentration of these constituents not only differs from manufacturer to manufacture, but they are also different from bottle to bottle from the same manufacturer.
What is a Certified Vodka?
Deeming whether a vodka brand or bottle is safe or “pure vodka” is very tricky for analytical chemist since they have to make numerous comparisons. The bottle’s anion-cation and fusel oil composition is usually compared between manufacturers of the same kind of vodka, between bottles from different years from the same manufacturer, and between the bottle in questions and denatured/adulterated bottles. In addition, the country of origin is of great concern. For example, spirits bottled in Russia and in Germany display large differences ("Lachenmeier, 105-110")). The concentration of anions in Russia vodkas tend to be lower than German ones, 0.2 – 7.2 mg/l compared to 11.5-147.6 mg/l ("Lachenmeier, 105-110"). Despite all of this variance, analytical chemist rely on the fact that premium vodkas, such as Smirnoff Vodka, tend to have very low anion and fusel oils concentrations due to the use of premium ingredients and manufacturing techniques such as ion exchange or reverse osmosis for deionization ("Lachenmeier, 105-110"). Whereas manufacturers of cheaper brands tend to bottle their vodkas with standard tap water without further water treatment and cheaply distilled ethyl spirit, therefore their vodkas tend to have higher ionic and fusel oil concentrations ("Lachenmeier, 105-110"). The methodology of comparing of a bottle’s anion-cation and fusel oil composition between manufacturers of the same kind of vodka, between bottles from different years from the same manufacturer, and between the bottle in questions and denatured/adulterated bottles as a mean of certification of the bottle has been conducted by several analytical chemist in their experiments; experiments such as “The Use of Ion Chromatography to Detect Adulteration of Vodka and Rum” by the Drik W. Lachenmeier group, and “Identification of Vodkas by Ion Chromatography and Gas Chromatography” by V.N. Arbuzov and S.A. Savchuck, have successfully identified the difference between pure vodkas and adulterated/denatured by means of comparisons.
How Certification Works
In “The Use of Ion Chromatography to Detect Adulteration of Vodka and Rum” by the Drik W. Lachenmeier group, they determined that the suspicious vodka samples were in fact suspicious by comparing the quantity of acetaldehyde and isoamyl alcohol (determined by GC), and chloride, nitrate and sulphate (anions determined by IC) between authentic Smirnoff, authentic German Vodka and the suspected Smirnoff vodka samples. The suspected Smirnoff vodka samples were found to truly be German Vodka. According to the study, the authentic Smirnoff and German Vodka sample had similar concentrations acetaldehyde, isoamyl alcohol and percentage per volume of ethanol, but concentrations of chloride, nitrate and sulphate that were not detected in the authentic Smirnoff were present in the authentic German vodka samples. The nitrate concentrations were found to range from 14.5 to 12.8 mg/l in the three vodka samples and 15.5 mg/l in the German vodka sample. The chloride concentrations were found to range from 8 to 9.3 mg/l and 9.3 mg/l in the German vodka sample. The sulfate concentration was found to range from 15.5 mg/l to 21.2 mg/l and 17.1 mg/l in the German vodka sample (refer to figure 3). The data collected clearly proved that the bar was guilty of an act of fraudulence. In addition, the group analyzed different brands of vodkas to have a quantified idea of the composition of a good sample (refer to figure 2). V.N. Arbuzov and S.A. Savchuck conducted their experiment in a similar manner (their investigation occurred before that of Drik W. Lachenmeier group).
Figure 9: Comparison of different brands vodka by Lachenmeier group ("Lachenmeier, 105-110")
Figure 10: Comparison of suspected vodka samples by Lachenmeier group ("Lachenmeier, 105-110")
In V.N. Arbuzov’s and S.A. Savchuck’s paper, “Identification of Vodkas by Ion Chromatography and Gas Chromatography”, the authors argued that the co-analysis of vodka by IC and GC-MS is better than solemnly analyzing vodka by GC-MS. Like Drik W. Lachenmeier’s group, V.N. Arbuzov and S.A. Savchuck based their conclusion on the comparison of concentration of anion-cation and impurities in vodka between the sample and control (refer to figures 4, 5 and 6). For example, when comparing the concentration of acetaldehyde, ethyl acetate, methanol, 1-propanol and 2-propanol between Charka vodka and it’s adulterated form, the concentration of acetaldehyde, ethyl acetate and 2-propaol were higher in the adulterated form and the concentration of methanol were lower in adulterated vodka. They also found differences in the ionic composition of the Charka vodka and its adulterated form where sodium, sulfate, potassium and chloride were higher in concentration in Charka vodka than in its adulterated form, and nitrate, calcium and magnesium were lower in concentration in Charka vodka than in its adulterated form. This data provided them with a benchmark, a quantified definition of what proper Charka vodka was composed of. With this data, they could have easily determined whether a manufacturer or bar owner was guilty of fraud. In addition, the two scientist collected data on the concentrations of ions and impurities for bottles of different trades and bottles form different years from the same trade. Similar to Drik W. Lachenmeier’s group, that data was used to prove how ion chromatography can effectively be used to detect trends in the ion concentrations of bottles from the same trade, thus providing the experimenters with more information as whether a bottle should be certified. Their papers are perfect examples of how chemists use GC and IC techniques to regulate vodka manufacturing.
Figure 11: Anion-cation analysis by V.N Arbuzov & S.A Savchuck between manufacturer and amongst a manufacturer with their adulterated forms ("Arbuzov, 515-521")
Figure 12: Impurities analysis by V.N Arbuzov & S.A Savchuck between manufacturers & their adulterated forms ("Arbusov, 515-521")
Figure 13: Impurities analysis by V.N Arbuzov & S.A Savchuck amongst a manufacture and adulterated form ("Arbuzov, 515-521")
Conclusion
As V.N. Arbuzov and S.A. Savchuck pointed out, the use of ion and gas chromatography is the most effective means of identifying, certifying and regulating vodka as it characterizes two major constituents of vodka, water and alcohol. As the demonstrated in the collected data by V.N. Arbuzov and S.A. Savchuck and the Drik W. Lachenmeier’s group, the difference in the composition vodkas, are quite similar. That is why chemist must rely on highly sensitive techniques such as GC and IC, to protect the public from potential harms and acts of fraudulence. GC provides them with information on the amount of impurities such as 1-propanol, 2-propanol, methanol, ethyl acetate and acetaldehyde while IC is better at collecting data on amounts of ions such as sodium, potassium, magnesium, calcium, chloride, and nitrate and sulfate. Although these constituents are found in small concentrations in most vodkas, even adulterated ones, they can prove to still be harmful to pregnant women and those with poor liver or kidney function. It is for the very same reasons that it is medically ill advised to heavily drink on a regular basis. Alcohol is poisonous to our bodies and techniques like GC and IC help governments protect society from intoxicating itself to death.
Citations